From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joakim Tjernlund Date: Tue, 3 Nov 2009 10:20:19 +0100 Subject: [U-Boot] Does uboot EBS(erase block summary) to reduce JFFS2 scaning time? In-Reply-To: References: Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de HeLei wrote on 03/11/2009 09:21:04: > > Thank you, Jocke > > > Subject: Re: [U-Boot] Does uboot EBS(erase block summary) to reduce JFFS2 > scaning time? > > To: leon.he at msn.com > > CC: u-boot at lists.denx.de > > From: joakim.tjernlund at transmode.se > > Date: Tue, 3 Nov 2009 08:41:08 +0100 > > > > > > > > > > Hi, All > > > > > > > > > > > > Each time JFFS2 initialized, uboot need to scan the whole flash. This is > > > fairly time consuming. > > > > > > > > > > > > So EBS(erase block summary) is used to JFFS2 to reduce mounting time. And I > > > believe this can also be used to UBOOT to reduce booting time. > > > > > > > > > > > > Does UBOOT support this feature? or does any other solution in uboot to > > > reduce JFFS2 scaning time? > > > > Don't think EBS is going to buy you much. The main problem is that the > > You mean even EBS is used in UBOOT, it will not give me much help. But it > seems there is great efficiency in jffs2 mounting, from some artical in > internet, such as:http://www.embedded-linux.co.uk/tutorial/jffs2-summary > > > scanning of JFFS2 in u-boot is inefficient. u-boot could take a > > hint from the kernel impl. of JFFS2 to reduce scanning. The biggest > > ones are: > > - do no scan the whole EB when it is empty. > If we don't scan the block, how can we tell the EB is empty? > > > - impl. a better crc32(use the one from linux) Attaching a very crude port of linux crc32. This boots a linux img for me and handles the environment crc as well. Feel free to clean it up and submit to u-boot. Jocke (See attached file: crc32-new.c)(See attached file: crc32defs.h)(See attached file: crc32table.h) -------------- next part -------------- A non-text attachment was scrubbed... Name: crc32-new.c Type: application/octet-stream Size: 16057 bytes Desc: not available Url : http://lists.denx.de/pipermail/u-boot/attachments/20091103/0e661951/attachment.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: crc32defs.h Type: application/octet-stream Size: 1072 bytes Desc: not available Url : http://lists.denx.de/pipermail/u-boot/attachments/20091103/0e661951/attachment-0001.obj -------------- next part -------------- A non-text attachment was scrubbed... Name: crc32table.h Type: application/octet-stream Size: 9976 bytes Desc: not available Url : http://lists.denx.de/pipermail/u-boot/attachments/20091103/0e661951/attachment-0002.obj